Means for grinding blocks



Dec. 22, 1925- A. E. GRAY MEANS FER GRINDING BLOCKS Filed Aug. 27, 1921 W/T/VE8SES 2 Sheets-Sheet 1 I/ VENTOR INVENTOR A E GRAY MEANS FOR GRINDING BLOCKS Filed Aug. 27, 1921' Dec. 22, 1925' MT/VESFES Patented Dec. 22, 1925.

UNITED STATES,

PATENT OFFICE.

ARTHUR E. GRAY, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO PITTSBURGH CLAY POT COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA. I

MEANS FOR GRINDING BLOCKS.

Application filed August 27, 1921. Serial No. 495,868.

To all whom itma-y concern:

Be it known that I, ARTHUR E. GRAY, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have made a new and 'us"ef ul Invention in Means for Grinding Blocks, of which the following is a specification.

This invention relates to a new and improved means for grinding blocks such as tank blocks.

An object of this invention is to produc an improved means for grinding blocks by means of which truerblocks may h e-obtained and chance of spoiling the block after the grinding operation has been completed is minimized.

A further object is to produce a new and im roved method of grinding blocks inwhlch the possibility of errors in grinding, resulting fromerrors in setting up, is reduced to a minimum.

A further object is to produce a new and improved grinding machine inwhich means are employed for simplifying the operation of setting up the blocks for the successive grinding operations to which they are subjected. 1

These, and other objects which will be made more apparent throughout the further description of. the invention are accomplished by means of the apparatus herein illustrated and described.

In the drawings forming a part hereof, Figure 1 is an end elevation of a machine embodying myinvention. Parts of the machine a're shown in section for convenience of illustration. Figure2 is a fragmentary plan View of a portion of the apparatus illustrated in Fig. 1v and Fig. 3is a side elevation of the portion of the apparatus illustrated in Fig. 2.

In the operation of grinding blocksand particularly tank blocks used in building glass tanks and similar structures, theblocks are ground very carefully since they are usually assembled Without employing grouting or cementing material between them. The grinding of such blocks is, therefore, an expensive operation, since-the opp site sides of each block must be paralhl and each of at least five surfaces of the block must extend at right angles toeach of the other surfaces. This is ordinarily accomplished by settmg up the block to be ground on the. table of the grinding machine before each grinding operation is started. This operation takes time and requires considerable skill. If the operator is unskillful, the block is spoilediby grinding one face out of true. One of the objects of the present invention is to simplify the operation of setting up the blocks, reduce the cost ofgrinding blocks and at the same time, minimize the chance for error in finishing the blocks.

Referring to the drawings,block grinding machinesare usually equipped with an annular grinding wheel 4 on which the grinding or abrasive material blocks 5 are so mounted that they present an annular grinding faceto. the block to be ground. The wheel is usually mounted on a carriage similar to the carriage 6 illustrated in Fig. 1- i which is mounted on a bed 7 .and is movable toward and away from a grinding table 8 als mounted on the bed 7. The grinding table is mounted on ways on the bed 7 and is adapted to reciprocate insucha way as to move the block to be ground across the grinding face of the wheel 4. It will, of course, be apparent that some means such as a motor 9 is employed for turning the wheel 4 and that the table 8 is preferably mechanically actuated and that automatic means are preferably employed for moving the grinding wheel toward the grinding table after each reciprocation of the table.

In carrying out my invention, I employ a supplemental table 10 which is adapted to be mounted on the table 8 and on which the block or blocks 11 to be ground are mounted. The table 10 may be constructed in any manner which will ensure sufficient strength and rigidity, but 1' preferably provide it with a series oflongitudinally extending, parallel anchor bolt-receiving channels '12 similar to the channels- 13v ordinarily fprd vided in the supporting face of the table of a grinding machine. The table 10 may als be of any, suitable. length or width, its

by the size of the grinding table 8 with which it is associated. In Figs. 2 and 3,

1 have shown a convenient means for mounting the supplemental table 10 on the table 8 of a grinding machine. As there illus trated, I provide an extension or lug 14 on each end of the table 10, each of which is in turn provided with an aperture adapted to receive a centering and locking pin 15. As shown, each pin 15 is rigidly mounted on a block firmly secured to the table 8. The blocks 16 are preferably so formed that they extend across the entire width of the table 8 and are capable of being rigidly secured thereto by means of anchor bolts or other suitable clamping devices. Each block is also preferably provided with a plurality of pin-receiving apertures 17. Any suitable meansmay be employed for rigidly securing the 'pins 15 to their mounting blocks, for example, the lower end of each pin may be threaded and each aperture 17 may be tapped so that the pin may be screwed into the aperture. The blocks 16 arepreferably similar and particularly with relation to the positions of the apertures 17,

since it is essential tov so locate the centering pins at each end of the table 10 that the longitudinal axis of the table 10 will be absolutely parallel. to the direction of motion of the table'8. By employing similar blocks 16 and mounting pins 15, the operation of setting the table 15 in place on the grinding table 8 is simplified, although it will be apparent that any means may be employed for is also securely held in position. It will,v

of course, be understood that-the locking action of the pins 15 and wedges 18 may be supplemented by anchor bolts or other clamping devices. Y

I Before the table 10' is mounted on the table 8, one or more blocks 11 to be ground are mounted on it in the usual manner of mounting such blocks on a grinding table;

for example, anchor bolts 20, suitable holding bars 21 and clamps 23 may. beemployed. After the blocks are in place on the table 10, the table is positioned on and. secured to the grinding table 8 of the grinding machine, so that its longitudinal axis is parallel with the longitudinal axis of that table. Qne face of each of the blocks mounted'on the table is thenground. After this .-grind ing'operation, the table 10 is lifte'd fromthe table 8 and swung around and then mounted 011 the table 8 in a reversed position. \Vith the securing device illustrated, the turning eration is then continued and it will be apparent that this second grinding operation grinds the faces of the blocks opposed to those-previously ground. It will also be apparent that the faces ground by the secand grinding operation will be absolutely parallel with the faces ground by the first operation. After the second grindingoperation, the table 10 is removed and carried to the setting up bench where the block or blocks 11 are re-positioned for the purpose of presenting the other faces to the grinding wheel. Subsequent operations are carried forward in the manner above described. For the purpose of facilitating the handling of the table 10, I provide a bar 24 at each end thereof which is adapted to be engaged by crane hooks 'or chains. As illustrated, each end of each bar 24: projects laterally beyond the table 10 so that each bar may be engaged by two crane hooks or chains.

, Aside from the fact that my invention produces more accurate grinding, it is also adapted to shorten the non-productive periods of each grinding machine, since two supplemental tables may be provided for each grinding machine'and the operation of setting up the block or blocks on one supplemental table may be accomplished during the operation of grinding the block or blocks previously set up on the other supplemental table.

It will be apparent that the structure of the supplemental table may be varied materially to suit conditions of operation, size of blocks and thenumber of blocks to be ground at each grinding operation. For eX- ample, it may be desirable to cast the smalle1 tables, whereas with the larger tables, it may be more convenient and cheaper to construct them of rolled sections. I also wish it to be understood that I do not limit myself to the particular means illustrated for locking the supplemental table in place since any means which is effective in obtain ing an'accurate positioning of the supplemental table on the grinding table and adapts itself to a quick and accurate reversing ofthe table may be employed. I

While I have illustrated and described a single embodimentof my invention, it will be apparent that various changes, modifications, substitutions, additions andom-issions may be made in the apparatus illustrated without departing from the spirit and scope of my invention.

W'hat I claim is The combination with the table of a grinding machine of a supplemental work supporting table, fastening means secured to said grinding table and adapted to engage the ends of said supplemental table to secure it in predetermined relation to said grind ing table in either of its end for end reverse positions and means for securing work pieces on said supplemental table with a plurality of'faces exposed for grinding.

In testimony whereof, I have hereunto subscribed my name this 20th day of August, d

' ARTHUR E. GRAY. 

